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Superficial DCF:Parotid space
The parotid space is a pair of suprahyoid deep compartments of the head and neck. It is the most lateral of the major spaces of the upper suprahyoid neck. The parotid space is a roughly pyramidal space, the broad elongated base facing laterally, formed by cervical fascia overlying the superficial lobe of the parotid gland, and its apex pointing medially It is enclosed by the superficial layer of the deep cervical fascia. Contents * parotid glands * intraparotid lymph nodes * extracranial facial nerve (CN VII) * external carotid artery (ECA) * retromandibular vein Boundaries * Medially: the parapharyngeal space * Laterally: superficial space and subcutaneous tissue * Posteriorly: the carotid space ** posterior belly of the digastric muscle forms a variable portion of the posteromedial border of the parotid space and separate the parotid space lesion from the carotid space * Anteriorly: masticator space * Superiorly: external auditory canal; apex of the mastoid process * Inferiorly: inferior mandibular margin (although the parotid tail can extend further inferiorly below the angle of the mandible) The parotid gland is the largest of the salivary glands and secretes saliva via the parotid duct into the oral cavity. It is located in the parotid space. Divided into superficial and deep lobes by the plane of the facial nerve. Location: wrapped around the mandibular ramus and anterior to the mastoid process of temporal bone. The gland is roughly wedge-shaped when seen superficially and on horizontal sections. Parotid duct: Long excretory duct, emerges from the anterior border of the gland, superficial to the masseter muscle. The duct pierces the buccinator muscle, then opens into the oral cavity opposite to the maxillary second molar. Capsule: * own capsule from dense connective tissue, * false capsule by investing layer of deep cervical fascia. The fascia splits into the superficial lamina and a deep lamina to enclose the gland. Relations: * Laterally: the skin, superficial fascia, investing layer of deep cervical fascia and great auricular nerve (anterior ramus of C2 and C3). * Anteromedially: mandibular ramus, masseter and medial pterygoid muscles. A part of the gland may extend between the ramus and medial pterygoid, as the pterygoid process. Branches of facial nerve and parotid duct emerge through this surface. * Posteromedial relations: mastoid process of temporal bone with SCM and digastric, carotid sheath * Medially: superior pharyngeal constrictor muscle. Content: from superficial to deep # Facial nerve: exits stylomastoid foramen as single trunk; ramifies within PS lateral to retromandibular vein # Retromandibular vein # External carotid artery # Superficial temporal artery # Branches of the great auricular nerve # Maxillary Artery Blood supply * arterial supply: external carotid artery and its terminal branches within the gland, the superficial temporal and the maxillary arteries, supply the parotid gland. * venous return: retromandibular vein. Lymphatic drainage The gland is mainly drained into the preauricular or parotid lymph nodes which ultimately drain to the deep cervical chain. Innervation * Parasympathetic: ottic ganglion via postganglionic fibres in the auriculotemporal nerve, from the glossopharyngeal (IX). Inferior salivary nucleus and petrosal nerve to otic ganglion. Stimulation causes thin salivary secretion. Parotid gland salivation is ultimately caused by the glossopharyngeal nerve. * Sympathetic: From the cervical ganglia via the external carotid plexus around the ECA. Stimulation causes a thick mucous saliva. Normal variant accessory parotid gland